A comparative slang term that is used to indicate worthlessness in something. This term is a synonym of rat's ass, though it's slightly harsher(referring to a rat's vagina), less commonly used, and is known to be most often used by America's most loathed anti-gay fundie pastor Fred_Phelps and his congregation of similar-minded followers.
1."You jackass Swedes just don't get it. Once you have laws to chill Bible preaching, we don't give a rat's tutu whatever else you do or say. You are drippings from the Devil's own penis - a veritable sperm bank for Satan's queers." -Fred Phelps (to a few Swedes who sent him and his church photos of the Swedish royal family) BTW, this is quoted from his "church's" website.
2. Yay! Lots of beer for tonight's beirut tourn... whoa wait a minute, you bought us a few whole cases ofO'DOUL'S??!! You fucknob! That shit isn't even worth a rat's TUTU to drink! Now we really need to get into some gangsta shit with you for doing this to us!
Mark H. Over 1 year of Urban Dictionary contributions since last February(like anyone will give a rat's tutu? ;-) ).
2. Yay! Lots of beer for tonight's beirut tourn... whoa wait a minute, you bought us a few whole cases ofO'DOUL'S??!! You fucknob! That shit isn't even worth a rat's TUTU to drink! Now we really need to get into some gangsta shit with you for doing this to us!
Mark H. Over 1 year of Urban Dictionary contributions since last February(like anyone will give a rat's tutu? ;-) ).
by Mark H March 3, 2005
Get the rat's tutumug. Me and Katrina were talking and she said I love you and I accidentally said I juv tutu so now it’s an inside joke :)
by Aileen :) February 5, 2018
Get the juv tutumug. by Anal Sampans April 1, 2021
Get the Tutu no grumbomug. by EddieTheYetiStrikesAgain July 20, 2011
Get the Stinky tutumug. 
Testing, messing around with or just playing with. Sometimes used in preparation of being a bit carefree with your actions. The tutu is a poisonous plant of Aotearoa/New Zealand.
by Burnt Pixel September 2, 2021
Get the Tutumug.